Traverse mechanisms are much used in lathes, drill presses, recording devices and winding devices. Such mechanisms may take the form of a single threaded shaft, or a pair of threaded shafts having a follower, or carriage threaded thereon so that rotation of the one causes reciprocation back and forth of the other. Exemplary of such threaded shaft mechanisms are the devices disclosed in U.S. Pat. No. 952,005 to Fetherolf of Mar. 15, 1910 and U.S. Pat. No. 2,234,274 to Prinz of Mar. 11, 1941.
It has also been proposed to convert the rotary motion of an elongated shaft into reciprocating motion by the use of a friction, or "skew", roll which rocks, or swings first with one peripheral edge in angular contact with the shaft surface and then with the other peripheral edge in contact with the shaft surface. The friction rolls of the prior art have been journalled in a yoke, or fork, of a swivel shank turnable on its axis in a support, there being a coil spring between the support and yoke to press the roll in a direction normal to the shaft axis.
In U.S. Pat. No. 334,809 to Robinson of Jan. 26, 1886 the friction roll is supported in a swivel which is rocked to skew the roll and in U.S. Pat. No. 2,283,393 to Simons of May, 1942 the friction roll arm, or tiller, is oscillated by electro magnetism to skew the roll.
A tiller arm, which strikes spaced stops, is used to skew the friction roll in U.S. Pat. No. 2,539,667 to King of Jan. 30, 1951. A similar arm is used to skew the annular frictional drive gears disclosed in U.S. Pat. No. 2,940,322 to Uhing of June 14, 1960.
All of the above friction roll type traverse mechanisms are characterized by the friction roll being journalled in, or otherwise rotatable in, the yoke, or ring, of a swivel, the yoke being turnable on the axis of a swivel shank and the axis of the shank being normal to the axis of the shaft.